DEVELOPMENTAL POTENTIAL OF TRUNK NEURAL CREST CELLS IN THE MOUSE

The availability of naturally occurring and engineered mutations in mi ce which affect the neural crest makes the mouse embryo an important e xperimental system for studying neural crest cell differentiation. Her e, we determine the normal developmental potential of neural crest cel ls by performing in situ cell lineage analysis in the mouse by microin jecting lysinated rhodamine dextran (LRD) into individual dorsal neura l tube cells in the trunk. Labeled progeny derived from single cells w ere found in the neural tube, dorsal root ganglia, sympathoadrenal der ivatives, presumptive Schwann cells and/or pigment cells. Most embryos contained labeled cells both in the neural tube and at least one neur al crest derivative, and numerous clones contributed to multiple neura l crest derivatives. The time of injection influenced the derivatives populated by the labeled cells. Injections at early stages of migratio n yielded labeled progeny in both dorsal and ventral neural crest deri vatives, whereas those performed at later stages had labeled cells onl y in more dorsal neural crest derivatives, such as dorsal root ganglio n and presumptive pigment cells. The results suggest that in the mouse embryo: (1) there is a common precursor for neural crest and neural t ube cells; (2) some neural crest cells are multipotent; and (3) the ti ming of emigration influences the range of possible neural crest deriv atives.